Hi Ravi,
You can learn a lot from old things. Take a look at this
Electronic lock at this web site
http://members.aol.com/cpu8052/4013lock.gif. It has all of
the features you are trying to design into your program.
Learn from it and copy it into your design. That way you
will get the best of the old into your new design.
Regards,
Charles Bannister